James Wesley:
I appreciate your survival ideas over the years. Here, in the Caribbean, we use cisterns for water recovery quite a bit.
I’ve had occasion to make a cache lately from one of the smaller plastic cisterns, such as this one [1].
The tanks that come here (Cayman Islands) are black and configured somewhat differently, but same basic idea. They employ a screw-top opening, which can be weatherproofed against all but profound water pressure.
I set mine — a 750 gallon tank — in the sandy loam and made sure that the bottom third was all clean fill, especially under the tank. I bedded around the upper 2/3 with fairly large, but smooth rock, and concreted around the circular opening, so I could keep it clear of dirt and grit. I used thread-seal tape and teflon pipe sealant on the threads of the lid, and it’s watertight, at least until such time as it is completely underwater (future hurricane?).
I took a piece of 3-foot x 3-foot starboard (polyethylene) and cut it in an irregular shape, and glued sand and rock to it, such that when laid down over the opening, it appears uniform. I used polyethylene plastic rather than plywood, because it tends to not “echo” as badly when stepped upon.
Another idea that I’d like to mention: To prevent flour weevils in my stocked dry goods, I simply freeze each product (flour, pasta, beans, etc.) for 24-hours. That explodes the insect eggs, and they are good to go in preventing weevils after that.
Thanks again for all the time and effort. First time writing. Be safe. – B.L.